gzstream.cpp

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#include "soplex/spxdefines.h"
#ifdef SOPLEX_WITH_ZLIB

// ============================================================================
// gzstream, C++ iostream classes wrapping the zlib compression library.
// Copyright (C) 2001  Deepak Bandyopadhyay, Lutz Kettner
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
// ============================================================================
//
// File          : gzstream.C
// Revision      : $Revision: 1.8 $
// Revision_date : $Date: 2005/12/07 18:03:25 $
// Author(s)     : Deepak Bandyopadhyay, Lutz Kettner
//
// Standard streambuf implementation following Nicolai Josuttis, "The
// Standard C++ Library".
// ============================================================================

#include "soplex/gzstream.h"
#include <iostream>
#include <string.h>  // for memcpy

#ifdef SOPLEX_GZSTREAM_NAMESPACE
namespace SOPLEX_GZSTREAM_NAMESPACE
{
#endif

// ----------------------------------------------------------------------------
// Internal classes to implement gzstream. See header file for user classes.
// ----------------------------------------------------------------------------

// --------------------------------------
// class gzstreambuf:
// --------------------------------------

gzstreambuf* gzstreambuf::open(const char* _name, int _open_mode)
{
   if(is_open())
      return 0;

   mode = static_cast<unsigned int>(_open_mode);

   // no append nor read/write mode
   if((mode & std::ios::ate) || (mode & std::ios::app)
         || ((mode & std::ios::in) && (mode & std::ios::out)))
      return 0;

   char  fmode[10];
   char* fmodeptr = fmode;

   if(mode & std::ios::in)
      *fmodeptr++ = 'r';
   else if(mode & std::ios::out)
      *fmodeptr++ = 'w';

   *fmodeptr++ = 'b';
   *fmodeptr = '\0';
   file = gzopen(_name, fmode);

   if(file == 0)
      return 0;

   opened = 1;
   return this;
}

gzstreambuf* gzstreambuf::close()
{
   if(is_open())
   {
      sync();
      opened = 0;

      if(gzclose(file) == Z_OK)
         return this;
   }

   return 0;
}

int gzstreambuf::underflow()   // used for input buffer only
{
   if(gptr() && (gptr() < egptr()))
      return * reinterpret_cast<unsigned char*>(gptr());

   if(!(mode & std::ios::in) || ! opened)
      return EOF;

   // Josuttis' implementation of inbuf
   size_t n_putback = (size_t)(gptr() - eback());

   if(n_putback > 4)
      n_putback = 4;

   memcpy(buffer + (4 - n_putback), gptr() - n_putback, n_putback);

   int num = gzread(file, buffer + 4, bufferSize - 4);

   if(num <= 0)  // ERROR or EOF
      return EOF;

   // reset buffer pointers
   setg(buffer + (4 - n_putback),    // beginning of putback area
        buffer + 4,                 // read position
        buffer + 4 + num);          // end of buffer

   // return next character
   return * reinterpret_cast<unsigned char*>(gptr());
}

int gzstreambuf::flush_buffer()
{
   // Separate the writing of the buffer from overflow() and
   // sync() operation.
   int w = static_cast<int>(pptr() - pbase());

   if(gzwrite(file, pbase(), (unsigned int) w) != w)
      return EOF;

   pbump(-w);
   return w;
}

int gzstreambuf::overflow(int c)    // used for output buffer only
{
   if(!(mode & std::ios::out) || ! opened)
      return EOF;

   if(c != EOF)
   {
      *pptr() = static_cast<char>(c);
      pbump(1);
   }

   if(flush_buffer() == EOF)
      return EOF;

   return c;
}

int gzstreambuf::sync()
{
   // Changed to use flush_buffer() instead of overflow( EOF)
   // which caused improper behavior with std::endl and flush(),
   // bug reported by Vincent Ricard.
   if(pptr() && pptr() > pbase())
   {
      if(flush_buffer() == EOF)
         return -1;
   }

   return 0;
}

// --------------------------------------
// class gzstreambase:
// --------------------------------------

gzstreambase::gzstreambase(const char* name, int mode)
{
   init(&buf);
   open(name, mode);
}

gzstreambase::~gzstreambase()
{
   buf.close();
}

void gzstreambase::open(const char* _name, int _open_mode)
{
   if(! buf.open(_name, _open_mode))
      setstate(std::ios::badbit);

   // clear( rdstate() | std::ios::badbit);
}

void gzstreambase::close()
{
   if(buf.is_open())
      if(! buf.close())
         setstate(std::ios::badbit);

   // clear( rdstate() | std::ios::badbit);
}

#ifdef SOPLEX_GZSTREAM_NAMESPACE
} // namespace SOPLEX_GZSTREAM_NAMESPACE
#endif

// ============================================================================
// EOF //

#endif